Learning about the wonderful world of whisk(e)y and sharing the journey.

Scotch cask types – Seeking some clarity

Introduction

There are plenty of resources out there explaining how Scotch whisky goes from new-make spirit to full-fledged Scotch via maturation in casks (I’ll include some links at the bottom of this post). However, I decided to go ahead and do a blog post that pulls together some of that information. More specifically, I want to point out and discuss areas where I often see confusion and debate even amongst whisky enthusiasts. Hopefully I’ve got this down, but I’m open to correction if I’ve screwed anything up. 🙂

Scotch whisky, after being distilled, must be matured for at least 3 years in oak casks before it can officially be called Scotch. It’s right in the Scotch Whisky Association regulations. American oak (Quercus alba) and European oak (Quercus robur) are the most common species used for cask creation. Additionally, most Scotch whisky casks were previously used to mature bourbon or sherry. On a lesser scale, there are other types of previously used casks, such as Rum, Madeira, Port, Tokaji, and other wines. These are often used to “finish” a whisky after its initial maturation in sherry or bourbon casks, but can also be used for the full maturation period. Springbank 11 year “Madeira Wood”, for example, was matured entirely in ex-Madeira casks.

It’s all oak!

This brings me to the first point of confusion that I’ve witnessed. American oak bourbon barrels are the most common source for Scotch whisky casks. I’m not sure where it started, but it’s common to see the term “traditional oak” used to describe a whisky matured in ex-bourbon casks. I think in conversation, this sometimes gets shortened to “oak.” Now you have people talking about whether the whisky was matured in sherry or oak casks. Oak becomes a synonym for an ex-bourbon, American oak barrel. That’s very misleading.

All of these casks (bourbon, sherry, madeira, etc.) are made from oak. The maturation differences come down to type of oak, whether the wood on the inside of the barrel was charred or toasted, and what kind of (if any) liquid was previously matured in it. Scotch casks can also be re-used, which becomes another factor in the flavor and color profile of the whisky.

Update: Immediately after posting this, I saw a tweet advertising Black Bull 12 Year, along with the claim “Matured in oak.” This is the kind of lame marketing that adds to the confusion. Stating this on the bottle or marketing literature would seem to imply that it could have been matured in something else. Doesn’t it just make them come across as looking either dumb or condescending, and not like somebody you would want to buy scotch from? I supposed the practice could date back to before oak was called out as the required wood type. However, wouldn’t that at least make it “lazy” marketing at this point in time?

American oak. It’s not just for bourbon.

Myth: All American oak casks previously matured bourbon.

This is point of confusion #2. While it’s true that you can generally assume that a whisky matured in ex-bourbon barrels was matured in American oak, you can’t assume that an American oak cask was previously used to mature Bourbon. American oak is also used to make sherry casks. In fact, Highland Park uses ONLY sherry casks for the maturation of their standard line of whiskies. To adjust the flavors in their expressions, they play with the ratio of American and European oak casks used, as well as the number of times those casks have been refilled.

Stop giving me the stink eye

When I mention that HP only uses sherry casks, I seem to usually get met with a stink eye look. It seems to be very commonly believed that when Highland Park talks of American oak influence on expressions like the 15 year, they’re talking about ex-bourbon casks. However, their web site very explicitly states that they only use ex-sherry casks. I think part of the reason this is hard to believe is that when you think sherry, you don’t think of America. However, keep in mind that using American oak for sherry doesn’t require that the casks were actually made and used in the United States. The wood can be shipped to, coopered and seasoned in Europe.

I actually wondered about this myself. I believe HP when they say they only use sherry casks, but how do they get the quantity of American oak sherry casks that they need? Then I read James Saxon’s blog post about his Highland Park distillery tour. Here’s how his guide explained it to him…very enlightening!

They have the most dedicated wood policy in the industry – £2 million a year on casks and wood management. This is more than the rest of the industry combined. This was the first I’d heard of it. When it comes to wood, it is Glenmorangie which toots its horn the loudest. Well, like Glenmorangie, Highland Park has its own forests in America where they harvest the wood, lend them to the Sherry industry, then bring them back to Orkney to mature Highland Park. There are no Bourbon barrels in the place, just American oak seasoned in Europe in addition to European oak.

Great stuff! I highly recommend reading the rest of James’ Highland Park tour description, and checking out his other distillery tour reviews on the Scotch Odyssey Blog.

New Oak. Also not just for bourbon.

Myth: Scotch whisky MUST be matured in used casks.

Scotch is almost always matured in used casks, but there are exceptions. There is nothing in the Scotch Whisky Association regulations prohibiting the use of new (or “virgin”) oak casks in the maturation of Scotch whisky. Meanwhile, there ARE regulations stating that Bourbon must be matured in charred new oak containers. I can see where one might assume that a regulation exists dictating used oak on the Scotch side, but that’s not the case. They just choose to go with used casks to get the flavor profile they’re looking for.

Great resources for more information

Malt Madness Beginner’s Guide – The whole beginner’s guide at maltmadness.com is awesome. For information on casks and maturation, check out Chapter 5.

Whisky for Everyone – For a quick guide to the types and sizes of casks used to mature whisky, check out this very straight-forward blog post on whisky cask types and sizes.

World Whiskeyby Charles MacLean – This physical book is highly recommended, especially for the new whisky enthusiast, and served as one of my sources while writing this blog post. At $16.50 from Amazon right now, there’s no reason not to own this book. [No, my link does not earn me any kind of affiliate money]

The Balvenie Whisky Academy – The amazing Whisky Academy video series by The Balvenie includes a 10 minute video on Maturation in Module Two (You’ll need to enter your birth date before entering…Doh!). Satisfy your inner whisky geek and check out as much of the series as you can handle. 🙂

23 Responses

– The fact that Highland Park uses American oak sherry cask is due to the fact that the sherry industry itself is focusing more on American oak for their sherry maturation. European oak is simply too expensive, even for Spaniards who have the majority of European oak in the North of their country.

– A common misunderstanding is that sherry casks have been used to mature / store sherry. In fact most of the sherry casks are new oak casks that are quickly seasoned / impregnated with sherry. As such they’re not really “previously used” casks, they’re merely preparated.

Thanks for the excellent comments, Ruben! It’s great to get input from such a knowledgeable whisky enthusiast.

I mentioned “seasoning” briefly in my HP section, but failed to expand upon the concept. To tell you the truth, I’m not all that familiar with the practice (typical amount of time being “seasoned”, where the sherry came from, whether it’s used or dumped out, etc.).

The seasoned casks are still used, in the sense that they’re not completely “virgin” casks. However, it probably is a good idea to call them out separately from casks used to fully mature sherry.

Excellent write-up, but you distracted me with the picture of the Balvenie 14yo Caribbean Cask. Just picked up my second bottle of that expression over the weekend and it’s sitting on my table at home ready for me to open tonight.

This article just whet my appetite for more information on casks. I’m curious to know more about the process that goes into picking casks, the amount of charring each distiller uses on the used casks and the history behind the industry banning casks with mixed staves. Thanks again for the intro!

Hi Sean,
Thanks for stopping by! That Malt Madness link at the bottom of my post should help out with quite a bit of the info, but certainly won’t have all of the answers. Some of that (like amount of charring and picking casks) is going to vary from distiller to distiller, and even expression to expression.

Great stuff, Jeff. I remember you and I having the HP conversation over Twitter a couple of years ago and I was amazed that HP has no bourbon on site — crazy!

FYI — Lagavulin have a distillery only bottling at the moment that is the Distiller’s Edition release (partially aged in PX casks) finished in casks that have had sherry “power washed” into the wood. I have no idea what that adds to the aging but I liked this version more than the standard DE.

Finally, I appreciate the clarity re: the use of charred casks that have never held alcohol. The recent #35.35 release from the SMWS and the upcoming Alligator from Ardbeg both draw attention to the fact that used casks aren’t necessary to produce Scotch.

Great post, Jeff. It can be confusing making sense of casks when every company uses slightly different processes and a different communications/marketing vocab.

For me the question is how many times can a cask be used and still be called a bourbon or sherry or madeira or whatever cask?

I know that for Balvenie, we say ex-bourbon or ex-sherry only for the first time a cask has been used for Scotch whisky. After that, we call them “traditional oak” or “traditional casks”

I think it is a bit disingenuous when companies say “we only use 100% sherry casks” when many of the casks are re-re-re-re-filled. Again, when does a cask cease being ex-whatever?

Perhaps it would be easier and more honest if everyone said ex-bourbon, ex-sherry for first fill and American Oak or European Oak for refills.

However, as you point out with HP, varied practices amongst distillers make this less and less black and white and as we will certainly be seeing more and more treated/seasoned casks, their oak species becomes less aligned with their regionall spirits (sherry, bourbon, port, etc)

Wow, thanks for that great information, Sam (err…Dr. Simmons)! Especially for offering up an explanation (at least one interpretation) for the term “traditional oak/casks.” That particular use totally make sense! It’s hard to know what different distilleries and marketing departments are saying with some of these terms and phrases.

Focusing on the differences between first fill, refill, and multi-refill is a good distinction, and probably should have some standard terminology around it.

In HP’s defense, their marketing literature DOES associate the flavor differences to the type of wood more so than how the cask was previously used. They’re also fairly forthcoming on their use of refill casks. Although, I don’t expect distilleries to get too specific when describing the exact proportion of first fill, refill, etc. I mean, that’s all part of the “secret recipe”, right?

Anyway, your insight was very helpful, and I really appreciate your taking the time to share it on my little blog.

Yes, that would be interesting to hear whether there are any significantly different flavor characteristics coming from the Bulgarian oak. That’s certainly the case with American vs French/Spanish vs Japanese. The whiskywise article I linked to above talks about why Oak is good for casks. I would think Bulgarian oak would satisfy the same major criteria.

I’ve also read a couple of times about a much higher percentage of sherry casks being sourced from American oak, but nothing I felt was reliable enough to include in this article as a source. I wonder what the numbers are like.

Excellent post! I have written several times re: wood for aging whisk(e)y in the past, but never touched on these points. I just added you to my blogroll (I already “like” your Facebook page…I don’t know how I missed adding you to my blogroll — sorry!).

Hi Jeff,
Thanks for the link – and I’m delighted you find the whole subject of oak maturation as fascinating and note-worthy as I do.
We had a recent tasting courtesy of Glenfarclas (write-up to follow at the weekend) and their approach to oak is very interesting indeed – twice-yearly trips out to Spain to source just the write cask. If you’re paying £700 per cask it is worth your while to do so.
On the matter of re-re-re-refill, that is why I love Compass Box’s approach on the matter. John and his cooper estimate that the typical cask is used by the Scotch whisky industry 6 times which, in his view, barely makes it an effective maturation vessel any more, let alone capable of indicating its bourbon or sherry provenance back in the mists of time.
A very important discussion.
James

Hey James,
No problem on the links…thank YOU for such great details on the tours. That’s going to be SO helpful when I finally get around to making a trip to Scotland and figuring out where to go.

Wow…I hadn’t heard that 6 times was “typical” for number of refills. I wonder 1) whether they would actually go six rounds without re-torching the barrels, and 2) if they’re more forgiving of # of refills if they know it’s going into a blend vs single malt.

Hi Jeff,
That is precisely why I undertook the Odyssey: so that others would have a bit more information and a fellow-tourist’s perspective on the various packages on offer in Scotland. I hope it won’t be too long before the Scotch Hobbyist is making a nuisance of himself in the warehouses of Scotland!
The more often the cask has been used (and so sophisticated are the systems for keeping track of casks these days that anyone filling into wood will have the information regarding its history should they wish to use it) the more likely it will be put towards a blend. Your typical second fill Bourbon cask will most likely have had Scotch grain whisky in it for a few years (3-5, if I remember rightly) previously and likewise, fourth, fifth etc. will be containing malt whiskies destined for the lighter, cheaper blends. Lightness is important to note, because a more neutral cask in terms of flavour is also a blender’s prerogative. As we all know, though, livelier oak makes things a lot more interesting.
Thanks again,
James

This was a very good thread, Jeff. Of course you have mentioned in your myths section but it’s worth stressing, that the reason we see most casks of American [white] oak, is in the regulations state-side: “Meanwhile, there ARE regulations stating that Bourbon must be matured in charred new oak containers”: New oak casks meaning there, they are only used ONLY once and so to all intents and purposes disposable! Whether, France, Spain or Bulgaria has the resources or not, those cost more and may well become a commodity in their own right, but cost-benefit analysis may not hold water [of life!].
While many sherry casks are not used for ‘maturation’ as we’d understand the term, there are those involved in the house “solera” processes which do pass muster and command a sovereign’s ransom!
There have been some horror stories in the early years of ‘finishing’ barrels and butts: Rather than being shipped complete, they were broken down at source to be re-coopered in Scotland!!!!!
Ouch……

Interesting post from smsmmns. Agreed it would be good to have that issue standardised. One will hear, “first-fill ex-bourbon”, “re-fill ex-bourbon” and beyond that….It’s probably subjective even with a paper trail.

Personally, I have a barrel just about in it’s final year at Bruichladdich. That barrel, I picked-up (literally and put it in my truck) back in the autumn of 2003 when they bottled their 15 Y/O “George T. Stagg”. I took it to Bruichladdich for their 2004 fill of Port Charlotte, but before then, that barrel came to the rescue (and I daresay a little “finishing”) of a fill of senior Glen Ord that needed a temporary home for a month. I will be filling her one last time as a private venture with either Glenglassaugh, Arran or Bladnoch. The Port Charlotte filling was ‘first-fill ex-bourbon’ (omitting the interloper) and the next and last filling will be the “re-fill ex-bourbon”. I intend to avoid any future problems with designation by turning the barrel thereafter into furniture of some kind….Or maybe even a classy dog-bed for a discerning companion. A deserved rest after some 37 years of continuous graft!